Mitsubishi FX3U-232-BD User Manual page 285

FX Series PLC User's Manual - Data Communication Edition
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9.2.6 On-demand error flag [M8128 and M8428]
These devices turn ON when an error is included in a specified value for data sending used with the on-
demand function.
1. Detailed contents
When the amount of on-demand data is incorrect, the on-demand error flag turns ON.
In all PLCs except FX
In FX and FX
3U 3UC
2. Cautions on use
While the on-demand error flag is ON, data sending is disabled for the on-demand function.
When sending data from a PLC using the on-demand function, set to OFF the on-demand error flag.
9.2.7 On-demand data word/byte changeover [M8129 and M8429]
These devices specify the unit (word or byte) of on-demand data.
1. Detailed contents
Use this device to specify the data unit sent using the on-demand function.
Set these devices to ON to specify "byte" (8-bit). Set these devices to OFF to specify "word" (16-bit).
In all PLCs except FX
In FX and FX
3U 3UC
2. Cautions on use
When the unit is set to "word", the amount of on-demand data units is equivalent to the number of data
registers for sending.
When the unit is set to "byte", two on-demand data units use one data register for sending.
Example: When the amount of on-demand data is "5", the amount of data registers for sending is "3".
9.2.8 Serial communication error code [D8063 and D8438]
These devices store the error codes during serial communication.
1. Detailed contents
When the serial communication error flag (M8063 or M8438) turns ON, a corresponding error code is stored
in these devices.
In all PLCs except FX
In FX and FX
3U 3UC
The error code list is shown below:
Error
Device
code
6301
D8063 6305
(ch1)
6306
3801
D8438 3805
(ch2)
3806
2. Cautions on use
Error codes are not cleared even after communication recovers its normal status.
Clear them by switching the PLC mode from STOP to RUN.
and FX PLCs using communication port ch1, M8128 turns ON.
3U 3UC
PLCs using communication port ch2, M8428 turns ON.
and FX PLCs using communication port ch1, use M8129.
3U 3UC
PLCs using communication port ch2, use M8429.
and FX PLCs using communication port ch1, an error code is stored in D8063.
3U 3UC
PLCs using communication port ch2, an error code is stored in D8438.
Error item
Parity, overrun or
The transfer data is abnormal.
framing error
When the station number was FF, any command other than "GW"
Command error
was received.
The received message was insufficient. Because normal message
Monitoring timeout was not received within the time-out time setting, the transfer
sequence was initialized.
Parity, overrun or
The transfer data is abnormal.
framing error
When the station number was FF, any command other than "GW"
Command error
was received.
The received message was insufficient. Because normal message
Monitoring timeout was not received within the time-out time setting, the transfer
sequence was initialized.
9.2 Details of Related Devices
Contents of error
9 Related Data
A
B
C
D
E
F
G
H
I
Apx.
D-83